The term "vehicle" usually conjures up a mental image of a machine, the primary purpose of which is to transport goods and/or people from place to place. However, there are certain types of vehicles configured. to perform a task in a relatively localized area with the vehicle transportation capability being rather ancillary to the vehicle's main purpose.
A vehicle of the latter type is a construction/digging machine known as a backhoe. A primary purpose of a backhoe is to excavate and move earth rather than to transport goods or people. Such a machine is not unlike a farm tractor in general appearance and in the fact that the operator faces forward to drive the machine. However, a backhoe differs from such a tractor by virtue of the type of implement with which it is equipped.
At its rear, a backhoe is equipped with a digging implement comprising a hydraulically-operated articulated boom to which is attached a digging bucket. The boom and bucket are not unlike a human arm (the "boom") and hand (the "bucket"). Digging is with the "fingers," i.e., the bucket teeth, pointing generally downward. The boom can be swung in an arc to, say, deposit earth on a spoil pile after it has been excavated. A backhoe may also have a front-mounted loading bucket in which instance the machine is referred to as a loader backhoe.
A common type of backhoe has an operator's seat which, when facing forward, gives the operator access to those controls, e.g., steering wheel, throttle, brakes and the like, used to transport the machine from place to place. When the seat is pivoted to face rearward (about 180.degree. from the forward-facing position), the operator has access to the hydraulic valve levers used to set the machine outriggers for stability and to operate the implement. Backhoes are commonly seen digging trenches for pipelines although backhoes can be (and are) used to perform many other digging tasks.
A way of describing a backhoe is that it has two "systems," namely, the implement system and the machine transport drive system. Such systems are susceptible to simultaneous operation. But since the operator faces in different directions, usually about 180.degree. apart, to perform such operations, the possibility of such simultaneous operation gives rise to certain concerns.
That is, after the operator has properly positioned the machine using the drive system (and while anticipating the digging task to be performed later), s/he may inadvertently try to use the implement to dig while leaving the controls in the drive or power mode. (It should be noted that such an error would not be made by an operator who is even minimally attentive.)
Persons in the field of machine design have recognized somewhat similar possibilities with other types of industrial machines. For example, U.S. Pat. No. 5,109,945 (Koga) involves a system used on an industrial fork lift truck. While such system detects when the truck operator leaves the seat, no operator signal is annunciated. And, of course, the Koga system is not suitable for use in applications where the operator does not leave the seat when performing any of plural tasks.
An apparatus and method which signals a vehicle operator when, coincidently, the vehicle transmission is in the power mode and the seat is pivoted away from the controls used to transport the machine would be an important advance in the art.